Udder infection of goats by coagulase-negative staphylococci

Infection of udder halves by coagulase-negative staphylococci in seven commercial goat herds was studied in conjunction with the California Mastitis Test (CMT). Nine different species were identified and only 10% of strains belonged to groups which could not be identified with any of the known Staphylococcus species. The most prevalent species were Staphylococcus epidermidis (47.7%) and Staphylococcus caprae (19.7%). About half od the coagulase-negative staphylococcal infections gave negative CMT scores. The score was independent of the species of staphylococci involved and the stage of lactation. About 60% of the coagulase-negative staphylococcal species isolated were reisolated in the identical half udder during the following lactation.